1. Field of the Invention
This invention relates to a polymeric framework or stent for mounting a trileaflet heart valve constructed of natural or synthetic materials, particularly for aortic valve replacement.
2. Description of Prior Art
Frame-mounted, trileaflet heart valves have been widely used for many years as a prosthetic replacement for defective aortic valves in humans. Natural tissue valves have been constructed by mounting gluteraldehyde-fixed porcine heart valves in a suitable framework or stent as described, for example, in U.S. Pat. Nos. 3,570,014, 3,755,823, 3,983,581 and 4,035,849. Similar trileaflet valves have been constructed from autologous and hemologous fascia lata and dura matter, and from heterologous pericardium mounted in a suitable stent as described, for example, in U.S. Pat. Nos. 4,084,268 and 4,172,295.
More recently, efforts have been directed to the development of totally synthetic trileaflet heart valves constructed from tubes and films of biocompatible polymers such as polyurethane. Such valves are also mounted in a stent as described, for example, in U.S. Pat. No. 4,222,126.
Valve stents of the prior art have been constructed of noncorrosive metals such as stainless steel and of plastic such as polypropylene or polyethylene. Plastic stents for porcine valves as described in U.S. Pat. Nos. 3,570,014 and 3,755,823 have an intricate design which requires fabrication by machining from a solid block of polymer at great expense. Plastic stents as described in U.S. Pat. Nos. 3,983,581 and 4,035,849 are of a simpler design and may be formed by injection molding. While such stents are inexpensive, it is somewhat difficult to attach the cloth cover with the recommended method of heat lamination.
It is accordingly an object of the present invention to provide an improved stent for mounting a porcine heart valve.
It is another object of this invention to provide a stent for mounting a trileaflet heart valve wherein the leaflets are constructed of natural or synthetic sheet materials.
It is a further object of this invention to provide a stent for a prosthetic heart valve intended for use in the aortic position.
It is a yet further object of this invention to provide an improved heart valve stent which may be injection-molded and still permit a cloth cover to be attached by stitching.
These and other objects of the present invention will be apparent from the ensuing description and claims.